Spark plug



Sept. 15, 1953 a. P. PHILLIPS 2,652,044

' SPARK PLUG Filed Oct. 1, 1951 /V//4//My Patented Sept. 15, 1953 SPARK PLUG Harold P. Phillips, Hastings, Mich., assignor to Hastings Manufacturing Company, Hastings,

Mich.

Application October 1, 1951, Serial No. 249,133

2 Claims. 1

This invention relates to improvements in spark plugs.

The main objects of this invention are:

First, to provide a spark plug which maintains its efficiency over a long period of time, and which may be economically produced.

Second, to provide a spark plug in which the ground electrodes are so mounted as to be protected against erosion and accidental mechanical injury in handling, and at the same time one in which the ground electrodes may be effectively and easily gapped or adjusted.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims.

A preferred embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a fragmentary elevational view of a spark plug embodying my invention, portions being broken away and shown in section, the spark plug being illustrated as mounted in a combustion chamber which is conventionally illustrated.

Fig. 2 is an enlarged inner end view of a portion of the electrode shell of my spark plug, portions being broken away and in section to illustrate structural details.

Fig. 3 is an enlarged fragmentary view illustrating one of the steps in the manufacture of my invention.

Fig. 4 is an enlarged fragmentary "view in section on a line corresponding to line 4-4 in Fig. 2.

Fig. 5 is an enlarged inner end view corresponding to that of Fig. 2 of modified form or embodiment of my invention.

Fig. 6 is a corresponding enlarged inner end view of another modified form, parts being broken away and in section to show structural details, a tool being illustrated in position for gapping one of the ground electrodes.

In the accompanying drawings the views are all considerably enlarged, this being done in the interest of clearness and convenience in the illustrations.

In the accompanying drawing I represents the wall of an internal combustion engine having a threaded bore 2 therein. The insulator shell 3 is provided with a reduced inner portion i having external threads 5 coacting with the threads 2. The insulator is designated generally by the numeral 6 and has a reduced portion 1 at its inner end projecting centrally into the shell. The insulated electrode 8 is mounted in the insulator, but as the details of the cementing or sealing of the insulated electrode within the insulator and the mounting of the insulator in the shell form no part of my present invention, they are not illustrated or described in detail herein.

All three of the embodiments of my invention illustrated include two ground electrodes 9. The shell 3 has slots l0 extending from its inner end edge and adapted to receive the electrodes 9 which are preferably of fiat section. The electrodes are disposed in the slots l0 and fixedly secured therein desirably by welding indicated at H, current and pressure being applied to the electrodes simultaneously to upset the electrodes within the slots and weld them to the Walls thereof, thereby providing an effective electric and heat transfer bond or connection for the electrodes to the shell. The electrode stock preferably has rounded edges l2 which insures a good conducting contact when the current and pressure is applied. The portions of the electrodes disposed in the slots are upset therein to the extent of completely filling the slots as shown in Fig. 4. The electrodes are thus supported with their inner ends free, and are entirely within the shell.

In the embodiment shown in Fig. 2 the shell is provided with a pair of adjacently positioned angularly spaced slots II] which are cut in the wall of the shell so that the electrodes are in parallel side by side relation with their inner ends in laterally spaced overlapping relation to the insulated electrode 8. There is a third and open slot l3 extending from the inner edge of the shell and disposed in a plane parallel to the ground electrodes 9 and extending through the center of the insulated electrode. This open slot is adapted to receive a tool such as a screw driver blade of proper dimensions, and fulcrumingly supported for engagement with the inner ends of either of the ground electrodes for adjusting them relative to the insulated electrode. In this connection it is desired to point out that different gapping is required for different engines, and that it is not commercially desirable to manufacture spark plugs desired for repair or replacement purposes gapped for each make of engine. The applicants invention permits the manufacture of relatively few sizes, and the electrodes thereof may be adjusted or gapped at the factory as a part of the inspection step for a particular engine for which the spark plug is designated to be used, or to compensate for the substantial variations in manufacture, and

embodiments.

also to enable the gapping adjustment of the electrodes for a particular engine in which they are to be installed for replacement purposes, and also in cleaning should adjustment be found to be desirable.

In the embodiment shown in Fig. 5 the slots ID are positioned so that the electrodes project in opposite directions with their inner ends spaced laterally from the inner electrodes, and with their ends in side by side overlapping relation thereto and to each other. In this embodiment open slots I3 are provided and disposed in angularly spaced relation to the slots I0 in which the ground electrodes are seated, the slots being generally opposed to the :imrer :ends of the ground electrode but in inwardly offset relation relative thereto. Thus positioned the slots provide a. very effective support for a tool for adjusting the ground electrodes laterally r01 gapping them relative to the insulated electrode.

In the embodiment shown in Fig. 6 .the slots 14 are diametrically opposed and are angularly spaced vrelative to the slots in which :the ground electrodes are secured, and are in general :in

opposed relation to the inner ends of the electrodes .to be engaged by an adjusting tool as indicated at 15. The same type of tool may be used in adjusting the electrodes in all '01"- the In all of the embodiments the electrodes are housed .within the shell and guarded thereby against accidental displacement or injury, andefiecti-vely protected against erosion in use.

Having thus described my invention, what I claim as new and desire :to secure by Letters Patent is:

1. .A spark plug comprising an insulator and an insulated electrode carried thereby and projecting from the inner end thereof, .a tubular metallic insulator shell tor said insulator, the insulated electrode being supported centrally :of and terminating within the shell, said shell having a pair of adjacent but angular-1y spaced slots extending axially from its inner edge, .the slots .of the pair being on opposite sides ,of ,a plane through the center of the insulated electrode, there being a third slot in the opposite side of the shell extending axially from its inner edge and in the plane of the insulated electrode, and ground electrodes disposed in said adjacent slots and fixedly secured therein in spaced parallel relation and with their inner ends within the shell and in laterally spaced side overlapping relation .to the insulated electrode and laterally spaced therefrom, said ground electrodes being within the shell and guarded thereby and bendably adjustable toward or from the insulated electrode, said third slot being open for fulcrumingly engaging a tool therein for engagement w'iththe inner end of either of the :said ground electrodes facilitating the adjustment thereof.

A spark plug insulator shell and ground electrode assembly comprising a tubular metallie-shell having a pair of adjacent but angularly spaced slots extending axially from its inner aedgatheislotsof the pair being'onaoppositefsides of a plane through the axial center=of the-shell, there being :a third slot in the opposite side of the shell extending 'axially from its :inner edge in the said plane 'of the axial center of theshell,

HAROLD :P. PHILLIPS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,940,324 Rabezzana Dec. 19, 1933 2,150,724 Nowosielski Mar. 14, I939 

